Pulsed-Gas Dynamic Spraying: Process analysis, development and selected coating examples

A new material deposition process, the Pulsed-Gas Dynamic Spraying process is introduced in this work. A description of the process physics and of the experimental set-up developed at the University of Ottawa Cold Spray Laboratory is presented. It is envisioned that this process could allow the feedstock particles to be accelerated to high impact velocities and intermediate temperatures (below melting temperature), in a non-reacting propellant gas. That way, the intermediate particle impact temperature would lead to lower required critical velocity compared to Cold Gas Dynamic Spraying that could be easily reached while preserving the chemical and microstructural composition of the feedstock powder particles in the coating. Selected examples of the variety of coatings produced with the system are presented, illustrating the potential of the process to deposit various materials.